Change No. 3, Joint Action of the Army and the Navy, 1935

J.B. No. 319-1 (Serial 653).

THE JOINT BOARD,
WAR AND NAVY DEPARTMENTS,Washington, June 28, 1940.

The following changes in Joint Action of the Army and the Navy
recommended by The Joint Board have been approved by order of
the Secretary of War and by the Secretary of the Navy and
should be made in all copies of this publication.

Add the following new pages.

Page Nos.

Subject matter

Id-Ie

Promulgation of Change No. 3.

Remove and destroy the pages listed below and substitute the
reprinted pages containing changes as indicated.

NOTE: References to Chapter VI are
not linked. This Chapter was extensively revised in Change No. 2,
which is missing from the edition available for this transcription.

--HyperWar

Section IPolicy for Coordination of Radio Activities of the Army
and Navy[»]

Joint Board reports, J.B. No. 319 (Serial No. 183), of January
16, 1923, "Utilization of the radio services of the War and Navy
Departments for the transmission of Government dispatches," and
J.B. No. 319 (Serial No. 253), "Proposed draft of Executive Orders
re regulation of radio in the event of war or national emergency,"
are rescinded. The following policy, approved by the Secretary of
War and the Secretary of the Navy, is published for information
and guidance:

Purpose of Radio Policy.

The purpose of this statement of policy is to establish an authoritative
basis for the coordination of the Army and Navy in the
development of radio material, the establishment of radio stations,
and in the conduct of radio activities.

Basic Policy.

The Army and Navy shall provide, control, and operate such
transmitting and receiving stations as, augmented by private and
other Government-owned radio facilities, will insure the existence
and availability upon the outbreak of war or other national emergency
of a militarily controlled, thoroughly indoctrinated radio system
adequate to meet the requirements of national defense, having
in view the prevention of undesirable duplication and the practical
and definite limitation on expenditure imposed by economy.

--137--

Primary Responsibility of the Army and the Navy in Radio Activities.

The assignment of primary responsibility to the Army or
to the Navy for radio activities serving a definite area or purpose
imposes upon the designated service the responsibility for the establishment
and efficiency of radio serving such area or purpose, but
allows the other service to use radio to serve the same area or its
own purposes of a similar nature, provided no serious radio interference is caused thereby.

In war time unity of command in certain areas or theaters of
operation may be assigned to the Army or the Navy, in accordance
with the approved War Plans, and radio activities therein will be
coordinated by the responsible commander of the service in which
such unity of command is vested.

In order to avoid uneconomical duplication in time of peace:

The Navy only shall operate radio apparatus of high power
(10 kilowatts in the antenna or greater).

The Army shall not handle overseas radio communications
commercially or for other Government departments except between
the United States and Alaska, nor operate upon frequencies which
will cause serious interference with Fleet or Navy overseas circuits.

Assignment of Primary Responsibility.

Subject to the provisions of subparagraphs (a) and (b) of the
preceding paragraph, primary responsibility is assigned as follows:

To the Army in radio communication--

With and between Army units wherever located.

Within the Territory of Alaska.

With and between Army vessels, excluding such vessels as
may be placed under Navy control.

To the Army in radio intelligence--

For the Army wherever operating.

To the Navy in radio communication--

For the establishment, maintenance,and operation of an overseas
radio service for efficient communication with and between Navy
units wherever located; this service to be available to all departments
of the Government and for commercial purposes.

For communication with insular possessions, the Panama
Canal Zone, and with foreign territory occupied by the Navy.

With and between ships at sea, exclusive of Army vessels,
except such of the latter as may have been placed under Navy control
in case of war or national emergency.

--138--

For the establishment and operation of radio-compass stations
along the coasts of the United States, Alaska, overseas possessions,
or occupied foreign territory.

To the Navy in radio intelligence--

For the Navy wherever operating.

War-time Jurisdiction over Nonmilitary Radio.

In time of national emergency, when directed by the President
according to law, the Army and the Navy will assume jurisdiction
as follows:

The Army and Navy shall each assume complete control over
such nonmilitary radio stations as may be allocated to them by the
President to augment their peace-time facilities.

For purposes of censorship and supervision over such nonmilitary
radio stations as are permitted to operate:

consistent with proper economy, be equipped to send and receive on
one of these common frequencies.

The radio field sets provided for the use of the Marine Corps
on shore shall be capable of intercommunication with the radio provided
for the operation of similarly equipped units of the Army.

The radio communication equipment provided for the vessels
of the Army Transport Service shall be of a character normally
provided for commercial shipping of the same general class and
shall be capable of sending and receiving on at least two frequencies
assigned by the Navy Department for Naval Transportation Service communication.

Coordination with Radio Stations of Other Departments and Civilian Stations During Peace.

Coordination of the operation of Government radio stations
with each other and with the operation of civilian radio stations in
time of peace will be governed by the provisions of the radio act of
1927 (secs. 6, 8, and 25).

Coordination of Development Programs.

The Chief Signal Officer of the Army and the Director of Naval
Communications will coordinate the peace-time radio operation and
operational development of the two services. The Chief Signal
Officer of the Army and the Chief of the Bureau of Engineering of
the Navy Department will coordinate their recommendation for the
procurement programs of the Army and the Navy and will coordinate
technical radio matters of joint concern to the two services.

Approved by the Secretary of War and the Secretary of the Navy June 24, 1927.

--140--

Section IIDoctrines and Guides Governing Communication (Signal) Effectiveness
in Joint Operations of the Army and the Navy

Subsection I--General

Effective signal communication in joint operations of the
Army and Navy requires--

The interconnection of the appropriate elements of the Army
and the Navy by the appropriate means of signal communications.

Joint communication (signal) training.

The preparation and proper distribution of important items of
information and instructions governing signal communication.

Appropriate provisions for communication security.

Adequate provision for cryptographing.

The information presented hereinafter should serve as a guide,
to indicate--

The elements that are to be interconnected during joint operations.

--141--

The distribution that should normally be given important items
of information and instructions governing signal communication.

The cryptographic systems to be employed in joint operations.

The essentials of a Joint Communication (Signal) Plan.

Miscellaneous considerations.--Details for communication
between the Army and the Navy shall be made by the senior
officers of the two services in the area concerned. The following items
are here presented for the guidance of all concerned:

Means and methods of communication.--All suitable means
of communication are to be considered available for joint use. When
a choice is available, the most reliable means should be selected, with
due consideration for speed and security. Attention is particularly
invited to the advantages of effecting simultaneous delivery of messages
to numerous addressees by radio broadcasting (F-method)
without obtaining a receipt, or by teletype in case addressees are all
on a teletype net. Scheduled F-method radio transmissions should
usually be on an especially prescribed frequency and should be regularly
copied by most addressees. Such transmissions should be relayed
to those addressees who either are not able to copy, or are not required
to copy them. However, F-method transmissions may be made at
any time on the same frequency as that usually employed for the
2-way R-method (i.e., in which receipts are obtained for each message transmitted).

[»]
Precedence.--In the absence of specific instructions to the
contrary, messages of the same precedence, whether originating in the
Army or the Navy, will be handled in the order of filing for transmission,
or of receipt for relaying. Messages are divided into precedence
groups to show the relative order in which they shall be
transmitted and acted upon. This order is as follows:

The URGENT designation is reserved for messages requiring
the greatest speed of handling. Any message
designated as URGENT will be sent immediately upon
receipt, except when communication involving another
URGENT message is being carried on. URGENT
precedence is reserved for use during combat, or when
combat is imminent, real or simulated, to indicate that
the message so designated conveys the most important
orders, information or request pertaining to the combat,

--142--

and thus requires immediate attention. A primary
example of this type of message is a so-called Army
"flash" message which is employed to report air observation
of surface or air forces and ground observation
of air forces. For joint communication purposes, an
Army "flash" message may be considered to be an
urgent message of the highest priority. A primary
example of a Navy message of the highest priority is a
major contact report.

The PRIORITY designation is reserved for messages of
less urgency than those entitled to URGENT precedence,
but of such nature as to warrant precedence
ahead of messages designated as ROUTINE or DEFERRED.
Any message designated as PRIORITY
will be transmitted before any routine or deferred
messages which may be awaiting transmission, but
transmission of a short routine or deferred message will
not usually be interrupted to send a PRIORITY message.

The ROUTINE designation is reserved for messages requiring
no special precedence. They are transmitted
in the order in which they are received or in such
order as will clear the traffic most expeditiously. Any
message designated as ROUTINE usually will be
transmitted before any deferred messages which may
be awaiting transmission, but transmission of a short
deferred message will not usually be interrupted to
send a ROUTINE message.

The DEFERRED designation is reserved for messages
requiring no special precedence, and whose delivery to
the addressee may be delayed until the beginning of
office hours following the day on which they are file.d.
This will sometimes necessitate transmission of Deferred
messages ahead of Routine messages, in order
to effect delivery before the time indicated.

Address and signature.--While all official messages will be
sent by authority of the commanding officer, no signature will ordinarily
be transmitted. Messages intended for an addressee on board
a ship or airplane, or within a command onshore, will be routed by
use of the appropriate call sign of the
ship,
airplane, or shore command.
Delivery to any specific addressee within the ship, airplane
or shore command is a function of the command to which delivered.

--143--

If call signs are assigned for joint use to particular commanders, as
well as to particular ships, airplanes and shore commands, such
commander call signs may also be employed to indicate routing,
addressees and originators.

Use of clear or cryptographic language.--The general rules
governing the use of clear and cryptographic language are set forth
in subsection IV of this chapter, wherein communication security
is discussed.

Operating instructions and procedures.--Operating instructions
are special instructions for transmitting, receiving, and when
required, for relaying messages. These instructions are set forth in
a separate restricted pamphlet entitled, "Joint Army and Navy
Radio Procedure."

Time.

The time of origin is the time at which the message is
released or authenticated by the originator. If this time
does not appear on the message, it will be the time when
the message is filed for transmission.

The time of origin in joint communications is expressed in
the 24-hour clock system and transmitted as a group of
four figures, the first two digits representing the hours
from midnight and the last two the minutes past the hour.

The date is expressed for joint communication purposes by
two figures preceding the time of origin, indicating the
day of the month. If the date number is less than ten,
it is always preceded by zero. For example, the first
day of the month is 01, and the tenth day is 10. "071626"
means date was 7th day of month, and time of origin was 1626.

The month and year may be added to the date and time of
origin group when necessary for reference purposes in
the text of messages. For example: "Your 071626
DEC 1938" means "Referring to your message, with
time of origin 1626 on the 7th day of December 1938 * * *".

--144--

In the text of messages, if times indicated are not given
particular descriptions, the time prescribed for use by
the originator shall be understood.

Addressees.--In drafting messages, the various classes of
addressees may be indicated:

Action addressees.

Information addressees.

Both action and information addressees.

Subsection II--Coastal Frontier Defense

Joint channels and means of intercommunication (See
ch. V, Sec. III, Par. 32h(3)
and Diagram I.).--The radio, visual, and
wire communication which may be required between the two services
in joint coastal frontier defense operations are indicated below. Certain
Army-to-Army communication circuits and certain Navy-to-Navy
communication circuits are also included where considered
desirable to indicate the more important of such circuits. No attempt
has been made herein to prescribe the number of separate circuits to
be provided between stations. The number and the type of circuits
should be determined in each case by the nature and amount of the
traffic to be transmitted and by geographical considerations. If
practicable, separate wire circuits should be provided for command,
intelligence, and administration.

Coastal frontier headquarters (Army).

Wire to: Various naval district headquarters within the coastal frontier.

Radio (2)* to: Various naval district headquarters within the coastal frontier.

Corps area headquarters.

Wire to: Nearest naval district headquarters.

Radio (2)* to: Nearest naval district headquarters.

Sector headquarters (Army).

Wire to: Nearest naval district headquarters.

Radio (2)* to: Nearest naval district headquarters.

Subsector headquarters (Army).

Wire to: Inshore patrol headquarters.

Radio (2)* to: Nearest naval district headquarters from
those subsector headquarters that are
identical with defensive coastal area
headquarters and harbor defense headquarters
and forts.

(2)* Indicates radio two ways--for transmitting and receiving, to be placed
in operation if wire is not available, or fails for any reason.

--145--

Radio (2)* to: Inshore patrol. This communication will
necessarily be on the frequency assigned
for communication between ships and inshore patrol headquarters.
Subsector headquarters normally only intercepts radio messages from the
inshore patrol to inshore patrol headquarters, but may transmit also, when necessary.

(For air command purposes) between squadron, group and higher commanders
of Army and Navy joint task force elements.

(For air and air-ground liaison purposes) between reconnaissance and
scouting airplanes, and the commander of the joint task force.
Also, between squadron, group, and higher commanders of Army
and Navy joint task force elements. Between reconnaissance
aviation or bombardment aviation and the following:

To elements of the fleet at sea (if present).

To the joint task force headquarters--air (Army or
Navy). Also, between pursuit, fighter, and bombardment
aviation and Navy air station and/or Army
aviation headquarters from which operating as well as
with the headquarters of antiaircraft regiments and
antiaircraft gun battalions (for recognition purposes).

Navy airplanes (1)* (5)*.

Radio to:

Army airplanes (in emergencies and/or when jointly engaged in a mission).

When Army or Navy airplanes are used jointly as a part of a task
force organization, the frequencies for communication would be as
prescribed by the Army or Navy commander of the task force.

When not otherwise specifically provided, Army airplanes will
work with Army ground stations and Navy airplanes will work with
Navy stations afloat or ashore.

In emergencies, if the Army wishes to communicate directly
with a Navy airplane, the Army will utilize a frequency which is
known to be guarded by that Navy airplane. Similarly, when the
Navy wishes to communicate directly with an Army airplane, the
Navy will utilize a frequency which is known to be guarded by that
Army airplane.

Airplanes will not be required to shift frequency for joint communication
purposes while in the air. Any airplane which is able to
communicate on more than one frequency at a time may do so when required.

(2)* Indicates radio two ways--for transmitting and receiving, to be placed in
operation if wire is not available, or fails for any reason.

(3)* In certain areas it may be practicable and desirable for communication purposes
to have various shore headquarters located in the same building, or sufficiently
close to facilitate intercommunication and cooperation.

--149--

It is expected that those various commands of the Army and
Navy, which may have need of information to be transmitted by
particular aircraft of either service, will, whenever practicable, arrange
to receive such information direct, by having receiver (intercept)
watches set on the aircraft frequencies involved.

Normally, all joint radio communication, except for command
purposes between airplanes in flight, should be by radiotelegraph.

Aircraft warning service.--The various elements of the
Army and the Navy involved in joint operations must be interlinked
with an Aircraft Warning Service Information Center in a communication
net that will insure the prompt reception and distribution of
warnings of the approach of enemy aircraft. While the elements included
in this net will vary according to conditions, the information
center should usually be connected with the following for the purpose indicated:

The reception of warnings from--

Civilian reporting stations.
Army elements:

Ground reporting stations.
Aviation elements engaged in missions which would enable
them to advise of approach of hostile aircraft.*
All Army elements in a position to report the approach
of hostile aircraft.

* Information Center radio receivers will intercept for this purpose the
normal frequencies which these elements are using.

--150--

The distribution of warnings to--

Army aviation headquarters for the warning of:†

Army aviation bases.
Army aviation elements.
Army aviation fields.

Air defense headquarters.† (When present in coastal frontier.)

Antiaircraft artillery headquarters.† (When an air defense
headquarters is not located in the coastal frontier or when
so located, it does not control all antiaircraft artillery
defense elements in the coastal frontier.)

Coastal frontier and/or Army or corps area headquarters (for
the warning of civilian population and Army ground elements
and establishments and establishments).&dagger

Preparation and distribution of communication (signal)
plans and instructions (See ch. VI, sec. VI, par. 77 and Sec. VIII,
par. 108a).--It will be necessary for each service to have certain items
of information and publications pertaining to the other service. The
items of information as well as the distribution should be prepared to
suit each operation. The importance of early preparation and distribution
of these plans and instructions should be impressed upon all
concerned. For illustrative "Joint Communications (Signal) Plan,"
see paragraph 173.

Subsection III--Joint Overseas Expeditions

The specific circuits for the movement overseas of a joint
overseas expedition are not herein presented diagrammatically, as
in the case of joint communication for coastal frontier defense, since
each joint overseas expedition presents a varied set of forces and conditions.
However, the following discussion is intended to cover all
major items concerning communication for any joint overseas expedition,

† These elements are connected by wire with the Information Center.
Aircraft warnings may be distributed by radio broadcast.

--151--

and to serve as a guide therefor. Diagram II should be
considered merely as a guide to indicate the joint circuits which may
be employed during the landing phase of an oversea expedition. The
circuits and the number and type thereof should be determined in
each case by the nature and amount of traffic to be transmitted and
by geographical considerations.

General (See ch. VI, sec. III, par. 54.)--Many of the
measures necessary to insure effective communication (signal) in
joint overseas expeditions must usually be completed prior to, and
during, the embarkation phase. Prior to this phase, the following
measures should be undertaken: (1) the design and production of the
appropriate equipment and publications which will be required for
communication (signal) between the Army and the Navy, and (2)
the training of communication officers and enlisted men of both
services that will participate in the joint overseas operations in the
use of prescribed joint communication procedure and methods.
During the embarkation phase, the necessary communication (signal)
plans and instructions should be prepared, distributed, and studied,
and the particular training required for communication and for security
should be undertaken.

General principles.--The following general principles which
concern communication have been established:

During the movement overseas, the Army and Navy commanders
of a joint overseas expedition, with their respective staffs, should
be embarked on the same ship, as should the commanders of a joint
attack force, and, where practicable, this method should be extended
throughout all echelons of command. Each transport should have a
communication center operated by Navy personnel. The complement
of this center will be augmented by the addition of Army personnel
who will remain on duty therewith until their services are no longer
required for the routing of messages pertaining to the Army. The
communication (signal) officers should be informed of--

The particular ships in which the commanders of their
next subordinate and next superior units are embarked.

The naval communication arrangements for handling
communications between the ships, mentioned in (1)
above, to the end that they may arrange for the transmission
of orders and information under the circumstances.

(See ch. VI, sec. II, par. 50-52.) The liaison officers exchanged
between the commands of the Army and the Navy should have copies
of the cryptographic systems of their own service for handling messages
applying particularly to that service. These liaison officers may
have messages transmitted in these systems, regardless of the service

--152--

operating the agencies of communication (signal), provided the
restrictions on communication (signal) then in effect, are not violated.

Have responsibility for shore-ship communication, and
communication with Navy boats used for landings.

Have the beachmaster establish a communication center
at each landing place to handle communication between
ship and shore. (See ch. VI, sec. VI, par. 101a.)

Provide a naval liaison detachment to accompany each
combat team to provide the radio and visual communication
and operation facilities necessary for effective
naval gunfire support of the combat team. (See ch. VI,
sec. VI, par. 93a, 94b and c.) (See also par. 168b.)

As soon as possible, the Army will establish all of its own signal
communication for combat, and, in addition, provide wire communication
and messenger service from the command post of each Army
combat team to the commander of the naval liaison detachment
assigned to accompany that particular unit.

The Army shore party commander will establish a message
center at each landing place and will connect by wire and messenger
service with the Navy beachmaster's communication center at that
landing place. (See ch. VI, sec. VI, par. 101a, c, and d, and sec.
VIII, par. 109).

Aircraft communication principles and aircraft warning
service.--So far as they are applicable to communication in a joint
overseas expedition, the principles set forth in paragraphs 160 and
161, in connection with joint coastal frontier defense, should usually
be observed.

Joint communication (signal) training.--The various
elements of the Army and the Navy to be jointly trained are indicated
below. In particular, training during the embarkation phase should
include communication between the elements which will have to
communicate during the landing phase, the familiarization by all
concerned with the cryptographic systems prescribed for all phases.

Army and Navy aviation elements.

Navy observation airplanes.--Even though Army observers
may be provided in Navy observation airplanes, it is
essential that Navy personnel therein be trained as
indicated below, since in the early phases of the landing
they will usually be required to undertake liaison,
reconnaissance, and Army artillery adjustment missions.

--153--

In communication with the ground units to be
supported during the landing.

In recognition of Army panel and pyrotechnic signals
used in lieu of radio.

In picking up messages from and dropping messages
to ground troops.

In addition, such Navy personnel should be cognizant
of so much of the communication plans and instructions
issued to ground troops as may be necessary for effective operations.

Navy reconnaissance and spotting airplanes.--The Navy
personnel engaged in air reconnaissance and air spotting
of Navy gunfire in support of landing operations should
be trained in the pyrotechnic and panel signals displayed
by ground troops, particularly those used to indicate:

Location of front lines.
Gunfire is falling short.
Lift gunfire to next objective.
Put down gunfire on a particular objective.

Navy observation airplanes with Army observers.--Army
observers who may be assigned to Navy observation
airplanes during the early phases of a landing on missions
involving liaison, reconnaissance, and Army artillery
adjustment should be trained in the use of the Navy
radio equipment and in Navy spotting procedure.

Combat aircraft task forces.--It is especially important that
the combat elements of the aviation task forces of both
services be jointly trained in communication (signal)
methods and procedure to the end that the highest
degree of effectiveness may be attained in the operations
of such joint task forces as will be required to support the
landing operations.

Other elements of both services.

Army ground elements.--All Army ground elements should
be trained to distinguish friendly Naval aircraft from
hostile aircraft. In addition, the personnel of those
Army radio stations that will be required to communicate
with Navy airplanes engaged in reconnaissance,
liaison, and Army artillery adjustment missions should
receive training in communicating with the Navy aviation
personnel that will be assigned to cooperate with
them in the actual landing. Elements of the antiaircraft
defense forces should be informed of the recognition
signals (visual or radio) that will be employed
by Navy aircraft operating in support of the landing.

--154--

Naval liaison and communication detachments.--Naval
liaison officers and Naval communication (signal) detachments
assigned to accompany the Army assault
elements (in order to handle the observation and communication
(signal) required to bring about effective
Naval gunfire support of the Army assault units) should
be trained in the use of--

The mobile field radio equipment required.

The Army visual (including pyrotechnic) signals,
particularly those used to indicate--

Landing successful.
Landing not successful.
Reached objective.
Location of front lines.
Gunfire is falling short; and lift gunfire to next objective.
Put down gunfire on a particular objective.

This liaison and communication personnel through
rehearsals in the embarkation phases should be familiarized
with the operations of ground troops and the
other means of communication that are available in
case it is necessary to use the Army Communication
(signal) system to get Naval messages back to the
commander of the Naval fire support group via the
Naval beachmaster (see par. 168b).

Liaison officers.--Liaison officers who are exchanged between
the higher elements of command of the two services
should be thoroughly familiar with--

Provisions governing responsibility for communications
during the various phases of a joint overseas expedition.

Actual command "set-up" of the communication systems.

Rules of both services governing communication security.

Communication officers.--All communication officers should
be made cognizant of the following, during the embarkation phase:

Special equipment.--The special communication (signal)
equipment that should be provided and with which the personnel
concerned should be thoroughly familiarized prior to and during the
embarkation phase consists in general of the following items (i.e.,
when normal equipment of the particular element will not meet the
needs of the situation):

Radio sets that will permit of intercommunication between the
airplanes of such joint task forces as may be established.

Radio sets for such Navy liaison detachments as are to accompany
the Army combat teams. These sets should be of appropriate size
and weight to permit ready transportation to all locations where an
infantry battalion command post may be established, and should
permit direct communication between the Navy liaison detachment
commander and the commander (and ship) of the Navy fire support
group which is supporting the operations of the particular Army combat
team. As it is probable that radio equipment now available for
this purpose may not be effective under all conditions to be encountered,
substitute means for this communication should be provided--such
as aircraft radio or Army wire back to the beachmaster and
thence by radio to ship concerned.

Cryptographic systems for joint communications during all
phases of the operation, including sufficient Army fire-control and air-ground
liaison codes to supply copies to all Navy observation airplanes
assigned to Army reconnaissance, liaison, and artillery adjustment missions.

Radio sets for the beachmaster, for the small boats, used in the
landing, and possibly for transports of such characteristics as to permit
direct communication between units linked, as shown in Diagram II.

Pyrotechnics for use in the landing boats and on the beach.
When Navy airplanes are assigned to Army reconnaissance, liaison,
and artillery adjustment missions, arrangements shall be made, if
practicable, to permit communication between the Army ground
stations and Navy airplanes.

Subsection IV--Communication Security

General.--

Classified communication between the Army
and the Navy will be divided into the following security classes:

Secret.--Messages and written communications will be
classified and marked secret when disclosure of the
information contained therein might endanger national
security, cause serious injury to the interests or prestige
of the nation or any governmental activity, or would be
of great advantage to a foreign nation.

--156--

Confidential.-Messages and written communications will
be classified and marked confidential when disclosure
of the information contained therein, although not endangering
the national security, might be prejudicial to
the interests or prestige of the nation, a governmental
activity, or an individual, or be of advantage to a foreign nation.

Restricted.--Messages and written communications will be
classified and marked restricted when information contained
therein is for official use only, or when its disclosure
should be limited for reasons of administrative
privacy or denied the general public.

Secret, confidential, and restricted messages and written communications,
plus the information contained therein, will be handled and
safeguarded in a manner appropriate to the classification, as defined
above, and in accordance with the instructions of the service(s) concerned.

The following doctrines will govern in the classification of messages
and the use of the various cryptographic systems:

Reliability, security, and speed.--Reliability is paramount
and shall never be sacrificed for security or speed.

Use of clear and cryptographic language.

In time of war or emergency, all messages to be
transmitted by radio, or by other means when
danger of hostile or unauthorized interception
exists, are cryptographed except in the following
cases: when the tactical situation is such that
time cannot be spared for cryptographing or the
information to be transmitted if intercepted by
the enemy could not be acted upon in time to
influence the situation in question,a commanding
officer or his authorized representative may
order the transmission of a message in plain
language. Such messages will be marked "Send
in clear", over the signature of the commander or
his authorized representative.

So far as practicable, during joint exercises and
joint communication training exercises, each
message will be given the same classification and
handling as would be given to the same subject
matter in war.

Mutual observance of classifications.--The classification of a
message with respect to security may be changed only
by the originator of the message or by superior authority.

--157--

Rules governing communication security.

The communications of one service must not be
permitted to compromise the operations of the other service.

Radiotelegraph is the preferred method of joint
Army-Navy radio communication.

The rules governing cryptographic security in the
Army and the Navy are based on the same
doctrines and are, in general, similar, Compliance
with the rules of either service should
insure the necessary cryptographic security.

Classified communication between Army and Navy commands
or units resolves itself into the following categories or echelons as
regards distribution of cryptographic systems:

Category A--Cryptographic systems used in communication
between special high commands of the Army and Navy.

Category B--Cryptographic systems used in communication
between all high commands of the Army and Navy.

Category C--Cryptographic systems used in communication
between intermediate commands of the Army and Navy.

Category D--Cryptographic systems used in communication
between smaller units of the Army and Navy.

The foregoing categories should, in general, be followed, but
may be varied, if necessary, at the discretion of the senior commander
of either service in each theatre of operation. The senior commander
of the other service shall be immediately notified.

The cryptographic systems prescribed for the various categories
will be used as circumstances require. For this reason, all commands
will be supplied with the cryptographic systems prescribed for lower categories.

The cryptographic systems authorized for safeguarding classified
communication for each category are prescribed in the documents
mentioned in paragraph 171a.

Only the prescribed cryptographic system shall be used for classified
communication between the Army and the Navy.

Classified communication between Army and Navy units of
categories A and B will be facilitated by an exchange of liaison and
communication (signal) officers between the Army and the Navy
elements involved.

--158--

[»]
Grouping of Army and Navy units into categories for
classified communication.--The categories authorized for classified
communication, and the Army and the Navy units grouped
therein, are as stated below:
Category A.

Army:

War Department.
Commanders, theatres of operations.
Commanders, field armies.
Any other commanders designated by the War Department.*

Navy:

Navy Department.
Commanders-in-Chief, United States Navy.
Any other commanders designated by the Navy Department.*

All commands listed under categories A, B, and C above.
Commanders of all mobile ground units down to and including
infantry battalions and cavalry squadrons.
Commanders, landing force combat teams.
Commanders, individual forts or groups (harbor defenses).
Army transports and mine planters.
Aircraft in joint operations.

* The other Department will be informed of the commanders designated under
this provision in order that all concerned may be notified.

--160--

Navy:

All commands listed under categories A, B, and C above.
Vessels of inshore patrol and offshore patrol.
Aircraft of inshore air patrol and offshore air patrol.
Coastal force vessels and aircraft.
Escort vessels and aircraft.
All vessels and aircraft (not a part of or attached to the
local defense forces) engaged in joint operations.
Commander, Marine Corps units down to and including battalions.

General instructions.

The authorized cryptographic systems for the categories of
classified communication, the distribution of the various systems and
the effective publications governing their use are prescribed in the
current editions of the following documents:

Army: SIGNAN.
Navy: CSP 817, 818, 819, 820.

The communication (signal) plans should normally prescribe
the cryptographic systems to be used.

For emergency use in peacetime by all categories of command,
the cylindrical cipher device (Army: M-94; Navy: CSP 488) shall be
used. A universal emergency key for use with this device shall be
determined jointly by the Chief Signal Officer and the Director of
Naval Communications and shall be communicated to both services
from time to time. CIpher keys for use in local emergencies shall be
determined locally and jointly by the senior commanders of the Army
and Navy units involved. The United States Coast Guard holds this
device and is furnished the universal emergency key by the Director
of Naval Communications.

Subsection V--Joint Communication (Signal) Plan

(See ch. VI, sec. VIII, par. 108-110).

General.--The joint communication (signal) plans (or orders)
for joint operations of the Army and the Navy (whether for coastal
frontier defense or joint overseas expeditions) will in general include
the following items, in the sequence indicated below:

Information.

Such information of enemy communication (signal) as may
be essential from the point of view of joint operations
of the Army and the Navy.

--161--

Such information of friendly commercial communication
facilities as are to be used or are available for use) as
may be necessary for the coordinated action of the two
services in joint operations.

Such information of the communication (signal) systems
of the two services as may be necessary for understanding
by one service of the capabilities and limitations of
the communication (signal) systems of the other service.

Such information of the aircraft warning service communication
system as is necessary to insure the prompt reception
and distribution of the information of approach
of hostile aircraft.

Such information pertaining to the command "set-up"
(i.e., location of the headquarters or command posts) of
the two services as may be necessary for the effective
installation and operation of communication (signal) system.

Designation of the time systems to be used for communication
purposes and in the texts of messages.

Instructions for the establishment and operation of such
special visual channels as may be required between
elements of the two services.

Wire.--Instructions necessary for the installation, operation,
and maintenance of such wire communications as may be needed
between the two services should include provisions for a wire teletype
(telegraph printer) or telegraph antiaircraft intelligence net and an
aircraft warning service net. (See Diagram I.) If required, authentication
instructions should be issued.

Messenger (or courier) service.--Instructions necessary for
the operation of a messenger service between Army and Navy elements
when practicable and necessary, should state schedules, means
of transportation, and whether officer or enlisted man.

Recognition signals.

Recognition doctrine.

List of the types to be used--day and night--with statements
of time when each becomes effective.

Guide for distribution.

Identifying silhouettes of--

Ships: Friendly and enemy.
Aircraft: Friendly and enemy.

--163--

Recognition signals (surface craft, submarines, and aircraft)--

Type or types to be used.
Prescribed signals or maneuvers.
Identifying marks on ships, special flags, lights, etc.

Communication security and cryptanalytic activities.--Such
instructions should be promulgated as may be necessary to insure
the coordination of the communication security activities of the two
services and the prompt exchange of technical information between
the cryptanalytic elements of the two services.

Codes and ciphers.

Such instructions as are not included in existing regulations
and publications concerning the codes, ciphers,
and cipher keys to be used in joint operations.

Guide to the distribution of codes and ciphers.

Commercial communication facilities.

Such allocations to the Army and the Navy as may be required.

Special instructions covering traffic to be handled by
commercial stations.

Subsection VI--Miscellaneous

Other joint communication requirements.--In addition
to the intercommunication necessitated by simulated or real joint
coastal frontier defense and joint overseas expeditions, intercommunication
may be necessary daily in peacetime for liaison purposes
between various units of the Army and the Navy (and the Coast
Guard), and when specially required in cases of earthquakes, flood,
riot, and other emergencies, both natural and man-made. During
neutrality, intercommunication may be necessary in the joint maintenance
of a patrol in United States coastal waters. For the purposes
indicated above, the doctrines set forth herein will, insofar as applicable, govern.

Footnotes

1.
Ch. IX--Revised and republished June 28, 1940. Section I of the revised Chapter IX is a republication
of old Section A with a redesignation of the section. Paragraph numbering of old Section A, 1 to 9, is
retained pending revision and republication of Section I. Section II is new matter replacing old Section B
the contents of which is withdrawn from Joint Action of the Army and the Navy, 1935, and issued as a
separate document under a "restricted" classification. Paragraphing in Section II begins with 156.

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